Tunable ring oscillator circuits are utilized in a number of computer systems for clock multiplication. Many chipsets sold by Intel® Corporation implement these ring oscillator circuits to maintain accurate clock signal multiplication. In many of these implementations, the real time clock (generally 32.768 kHz) is multiplied to 1 MHz. The 1 MHz clock is then used to run circuits within the computer system, such as the System Management Bus (SMBus) controller. The real time clock may continue to operate when the computer system's main clock generator has shut down because a battery is utilized to power the real time clock. This enables the platform to accurately track time even when it appears to be off.
There are cases where the real time clock may fail. This can be caused by too much capacitance on the real time clock piezoelectric crystal (such as if a human touches the crystal), a conductive path across the crystal leads (due to condensation), or voltage fluctuations in the analog oscillator. These cases have been observed in real systems. Additionally, the real time clock may increase in speed when the operating voltage unexpectedly increases and the real time clock may decrease in speed if the temperature in the system increases. Furthermore, there are also cases where the oscillator that outputs the real time clock may work intermittently or the oscillator may get stuck on a certain harmonic. Thus, there are many instances where the real time clock can unexpectedly fail or change in speed. In the past, this has required changes to hardware implementations to correct these problems.